FW:
Levy, Charles
Description
Collection
Title:
FW:
Creator:
Levy, Charles
Date:
4/4/2000
Text:
> -----Original Message-----
> From: Levy, Charles
> Sent: Monday, April 03, 2000 5:08 PM
> To: <Email Address Redacted>
> Subject:
>
> Dear List Serve Members,
>
> I am posting another draft of a question and answer for the American
> Academy of Physical Medicine and Rehabilitation's Limb Deficiency Study
> Guide. Please bear in mind that this is only a rough first draft. I have
> tried to avoid using brand names. Word counts prevent me from explaining
> in much greater depth. I would appreciate your comments. References are
> always helpful.
>
> I appreciate the help I have received in the past and will post final
> drafts in the future.
>
> Thanks,
>
> Chuck Levy, MD
>
> L.O. 3.3: Compare the advantages and disadvantages of individual
> components for an active transfemeral amputee.
>
> As with most of amputation medicine and rehabilitation, the solution for
> any individual patient is dependent on a host of factors including
> strength, sensation, size of the residual limb, available range of motion,
> cardiovascular fitness, skin integrity, presence or absence of scarring,
> financial and psychological resources, and intended use. The prescription
> for the active transfemeral amputee who is a rural auto mechanic, will
> differ from that of an urban sprinter, to that of an avid outdoors
> enthusiast or dancer. The discussion that follows is intended to serve
> only as general guideline, and not a substitute for individual assessment.
>
> There are a variety of components can be employed for a transfemeral
> amputee. Ideally, every amputeeÕs prescription should be generated
> individually taking in to consideration expected use, comfort,
> convenience, cost, and aesthetics. The following discussion assumes that
> the user has access to a prosthetist, and to commonly available
> componentry.
> The first choice is between endo- and exoskeleton designs. Because
> exoskeletal prostheses cannot be adjusted for alignment after fabrication,
> allow only a restricted choice of feet and knee units that can be
> incorporated into the laminated shell and tend be weigh more than the
> equivalent endoskeletal prosthesis they are by far the less common choice.
> However, because exoskeletal prostheses are more rugged and durable, they
> may be preferred for a lifestyle that includes exposure that would cause
> failure to a less hardy prosthesis. This might includes use in the woods
> or in industrial settings where the user might crawl or be exposed to
> snags and excessive grime. Exoskeletal prostheses also tend to demand less
> maintenance. This can be a very important issue for the user who for lack
> of finance or transportation, cannot access prosthetics service without
> great expense. Endoskeletal prostheses are modular in design, allowing
> relative ease of adjustment of alignment and replacement of parts. By
> being lighter, an endoskeletal prosthesis demands less energy expenditure
> for ambulation, and may be easier to suspend.
> The next choice, travelling from proximal to distal, is socket
> shape. The two basic designs of socket shape are quadrilateral and
> ischial containment. Despite the dearth of well controlled studies
> involving socket shape, the following generalities apply (Schuch, 99):
>
> 1) There is no absolute contraindication for either socket shape.
>
> 2) Chances of a successful fitting of a quadrilateral socket is more
> likely when the residual limb is longer with a firm residuum and intact
> adductor musculature. Ischial containment sockets are more successful
> than quadrilateral sockets for those with shorter, fleshy, unstable
> residual limbs.
>
> 3) Ischial containment is recommended for high activity sports
> participation and running; the quadrilateral socket has been recommended
> for geriatric and debilitated individuals who walk with the assistance of
> canes or walkers, thereby decreasing the medial lateral pelvic and trunk
> stability demands of midstance.
>
> Potential benefits of IC include improved proprioception, improved femoral
> adduction, enhanced suspension, less lateral displacement during the
> stance phase, and weight distribution to a greater area. The
> quadrilateral socket, with its posterior brim situated distal to the
> ischial tuberosity, may allow greater range of motion in flexion and
> extension, and facilitate sitting.
>
> A flexible socket with a rigid frame is recommended for the active user.
> this will accommodate changing muscle shape during contraction/relaxation
> to a greater degree than a simple rigid socket (Schuch, 99). Although it
> is less forgiving, rigid. sockets tend to be lighter and more durable.
>
> Total contact, suction suspension is preferred for the active user. The
> user pulls the residual limb into the socket with stockinette, lotion, or
> an elastic bandage ( newer materials with less friction are also being
> used). Excess air is evacuated with an expulsion valve usually located at
> the distal end of the socket (Kapp, 99). In this form of suspension, the
> patient is unencumbered by belts or straps. Instead, the prosthesis is
> suspended by surface tension, negative pressure and muscle contraction.
> To benefit from this method, the user must have a stable size in the
> residuum, and a certain amount of dexterity, cognitive skill, and
> visual-spatial ability. An alternative is roll-on suspension sleeves with
> a pin and a shuttle lock. Although these may allow easier donning and
> doffing, they still require the application of some hand dexterity,
> cognitive and visual-spatial skills. Roll-on suspension also presents the
> draw backs of additional weight, less durability, daily cleaning, and
> distal suction on the limb. Partial suction is a solution when one must
> accommodate scars or spurs but at the cost of auxiliary suspension (waist
> belts, etc.) restricted motion, poorer cosmesis and greater pistoning.
>
> Mechanical knees can be described by their axes and their construction.
> Single axis knees are simple and light weight, and thus often the choice
> of active users. Polycentric knees ( usually four-bar units) boast the
> advantages of improved stability, greater toe clearance in swing, and
> improve clearance in sitting. Unfortunately, this all comes at the price
> of increased weight, which often limits their appeal.
>
> Hydraulic knees are often the choice of active transfemeral amputees,
> although microprocessor and pneumatic knees are reasonable alternatives.
> As technology advances, the balance of advantages to disadvantages within
> these categories will almost certainly change. All three of these style
> of knees offers some type of variable resistance to facilitate a variable
> cadences of gait. Hydraulic knees traditionally have allowed the greatest
> range of variable cadence, while being durable enough to stand up to
> frequent hard use. However, these knees tend to be heavier than their
> counterparts. Microprocessor controlled units are capable of changing the
> flexion and extension resistance depending on the cadence of the user.
> This can enable ambulation at multiple speeds. The draw back to this
> choice is the increased expense and mechanical complexity involved.
> Pneumatic units are a lightweight alternative to hydraulic knees that
> allow variable cadence. These units are generally regarded as being less
> durable, and may even feel as if they bounce at the end range of
> flexion.
>
> A simple, ultra-lightweight pylon has been typical used to connect the
> foot to the knee unit. Several options may enhance function although
> adding expense and weight. Ankle units are a common addition to the
> transfemeral prescription. Adding a small amount of weight and expense,
> these units can absorb some of the rotational forces generated between the
> foot and pylon. Torque absorbers typically situate between the knee and
> pylon, can absorb additional the rotational forces and thus further reduce
> shear at the socket/residual limb interface. This allows a certain amount
> of twisting between the foot and the knee (ie golf). Torque absorbers
> are less common than ankle units, perhaps due to there greater weight and
> expense compared to ankle units. Shock pylons absorb some of the
> compressive forces transmitted to the residual limb during stance.
> Rotational units can allow 360 degrees of rotation at the knees. Besides
> offering the chance to confuse unsuspecting onlookers, these serve the
> practical purpose of allowing the legs to cross in a seated position.
> A host of feet are available to fit the active amputee. For the sake of
> discussion, the can be classified as economy energy storage feet ,
> high-level performance feet and multi-axial feet.
>
> The economy energy storage feet offer a good compromise between weight,
> price, and response. They offer some ability to flex during stance and to
> release during pushoff, but less than the high performance feet. These
> economy feet can often be combined with an ankle unit to improve response
> on uneven terrain. Typical examples of this category are the Seattle
> Lightfoot, Carbon Copy II and the Endolite foot.
>
> High performance feet (ie Flex-foot, Springlite) offer the highest energy
> return. These are the choice of runners, and those that value there
> performance on even terrain. These feet are relatively expensive and can
> be unforgiving on uneven ground. They cannot be combined with ankle
> units.
>
> Multi-axial feet are designed to accommodate variable terrains, allowing
> variable motion about the ankle. Depending on the design and the
> amputee's use, the may require more frequent maintenance. Like wise,
> these feet tend to be more expensive than the economy energy storage feet.
>
>
>
>
>
>
>
> From: Levy, Charles
> Sent: Monday, April 03, 2000 5:08 PM
> To: <Email Address Redacted>
> Subject:
>
> Dear List Serve Members,
>
> I am posting another draft of a question and answer for the American
> Academy of Physical Medicine and Rehabilitation's Limb Deficiency Study
> Guide. Please bear in mind that this is only a rough first draft. I have
> tried to avoid using brand names. Word counts prevent me from explaining
> in much greater depth. I would appreciate your comments. References are
> always helpful.
>
> I appreciate the help I have received in the past and will post final
> drafts in the future.
>
> Thanks,
>
> Chuck Levy, MD
>
> L.O. 3.3: Compare the advantages and disadvantages of individual
> components for an active transfemeral amputee.
>
> As with most of amputation medicine and rehabilitation, the solution for
> any individual patient is dependent on a host of factors including
> strength, sensation, size of the residual limb, available range of motion,
> cardiovascular fitness, skin integrity, presence or absence of scarring,
> financial and psychological resources, and intended use. The prescription
> for the active transfemeral amputee who is a rural auto mechanic, will
> differ from that of an urban sprinter, to that of an avid outdoors
> enthusiast or dancer. The discussion that follows is intended to serve
> only as general guideline, and not a substitute for individual assessment.
>
> There are a variety of components can be employed for a transfemeral
> amputee. Ideally, every amputeeÕs prescription should be generated
> individually taking in to consideration expected use, comfort,
> convenience, cost, and aesthetics. The following discussion assumes that
> the user has access to a prosthetist, and to commonly available
> componentry.
> The first choice is between endo- and exoskeleton designs. Because
> exoskeletal prostheses cannot be adjusted for alignment after fabrication,
> allow only a restricted choice of feet and knee units that can be
> incorporated into the laminated shell and tend be weigh more than the
> equivalent endoskeletal prosthesis they are by far the less common choice.
> However, because exoskeletal prostheses are more rugged and durable, they
> may be preferred for a lifestyle that includes exposure that would cause
> failure to a less hardy prosthesis. This might includes use in the woods
> or in industrial settings where the user might crawl or be exposed to
> snags and excessive grime. Exoskeletal prostheses also tend to demand less
> maintenance. This can be a very important issue for the user who for lack
> of finance or transportation, cannot access prosthetics service without
> great expense. Endoskeletal prostheses are modular in design, allowing
> relative ease of adjustment of alignment and replacement of parts. By
> being lighter, an endoskeletal prosthesis demands less energy expenditure
> for ambulation, and may be easier to suspend.
> The next choice, travelling from proximal to distal, is socket
> shape. The two basic designs of socket shape are quadrilateral and
> ischial containment. Despite the dearth of well controlled studies
> involving socket shape, the following generalities apply (Schuch, 99):
>
> 1) There is no absolute contraindication for either socket shape.
>
> 2) Chances of a successful fitting of a quadrilateral socket is more
> likely when the residual limb is longer with a firm residuum and intact
> adductor musculature. Ischial containment sockets are more successful
> than quadrilateral sockets for those with shorter, fleshy, unstable
> residual limbs.
>
> 3) Ischial containment is recommended for high activity sports
> participation and running; the quadrilateral socket has been recommended
> for geriatric and debilitated individuals who walk with the assistance of
> canes or walkers, thereby decreasing the medial lateral pelvic and trunk
> stability demands of midstance.
>
> Potential benefits of IC include improved proprioception, improved femoral
> adduction, enhanced suspension, less lateral displacement during the
> stance phase, and weight distribution to a greater area. The
> quadrilateral socket, with its posterior brim situated distal to the
> ischial tuberosity, may allow greater range of motion in flexion and
> extension, and facilitate sitting.
>
> A flexible socket with a rigid frame is recommended for the active user.
> this will accommodate changing muscle shape during contraction/relaxation
> to a greater degree than a simple rigid socket (Schuch, 99). Although it
> is less forgiving, rigid. sockets tend to be lighter and more durable.
>
> Total contact, suction suspension is preferred for the active user. The
> user pulls the residual limb into the socket with stockinette, lotion, or
> an elastic bandage ( newer materials with less friction are also being
> used). Excess air is evacuated with an expulsion valve usually located at
> the distal end of the socket (Kapp, 99). In this form of suspension, the
> patient is unencumbered by belts or straps. Instead, the prosthesis is
> suspended by surface tension, negative pressure and muscle contraction.
> To benefit from this method, the user must have a stable size in the
> residuum, and a certain amount of dexterity, cognitive skill, and
> visual-spatial ability. An alternative is roll-on suspension sleeves with
> a pin and a shuttle lock. Although these may allow easier donning and
> doffing, they still require the application of some hand dexterity,
> cognitive and visual-spatial skills. Roll-on suspension also presents the
> draw backs of additional weight, less durability, daily cleaning, and
> distal suction on the limb. Partial suction is a solution when one must
> accommodate scars or spurs but at the cost of auxiliary suspension (waist
> belts, etc.) restricted motion, poorer cosmesis and greater pistoning.
>
> Mechanical knees can be described by their axes and their construction.
> Single axis knees are simple and light weight, and thus often the choice
> of active users. Polycentric knees ( usually four-bar units) boast the
> advantages of improved stability, greater toe clearance in swing, and
> improve clearance in sitting. Unfortunately, this all comes at the price
> of increased weight, which often limits their appeal.
>
> Hydraulic knees are often the choice of active transfemeral amputees,
> although microprocessor and pneumatic knees are reasonable alternatives.
> As technology advances, the balance of advantages to disadvantages within
> these categories will almost certainly change. All three of these style
> of knees offers some type of variable resistance to facilitate a variable
> cadences of gait. Hydraulic knees traditionally have allowed the greatest
> range of variable cadence, while being durable enough to stand up to
> frequent hard use. However, these knees tend to be heavier than their
> counterparts. Microprocessor controlled units are capable of changing the
> flexion and extension resistance depending on the cadence of the user.
> This can enable ambulation at multiple speeds. The draw back to this
> choice is the increased expense and mechanical complexity involved.
> Pneumatic units are a lightweight alternative to hydraulic knees that
> allow variable cadence. These units are generally regarded as being less
> durable, and may even feel as if they bounce at the end range of
> flexion.
>
> A simple, ultra-lightweight pylon has been typical used to connect the
> foot to the knee unit. Several options may enhance function although
> adding expense and weight. Ankle units are a common addition to the
> transfemeral prescription. Adding a small amount of weight and expense,
> these units can absorb some of the rotational forces generated between the
> foot and pylon. Torque absorbers typically situate between the knee and
> pylon, can absorb additional the rotational forces and thus further reduce
> shear at the socket/residual limb interface. This allows a certain amount
> of twisting between the foot and the knee (ie golf). Torque absorbers
> are less common than ankle units, perhaps due to there greater weight and
> expense compared to ankle units. Shock pylons absorb some of the
> compressive forces transmitted to the residual limb during stance.
> Rotational units can allow 360 degrees of rotation at the knees. Besides
> offering the chance to confuse unsuspecting onlookers, these serve the
> practical purpose of allowing the legs to cross in a seated position.
> A host of feet are available to fit the active amputee. For the sake of
> discussion, the can be classified as economy energy storage feet ,
> high-level performance feet and multi-axial feet.
>
> The economy energy storage feet offer a good compromise between weight,
> price, and response. They offer some ability to flex during stance and to
> release during pushoff, but less than the high performance feet. These
> economy feet can often be combined with an ankle unit to improve response
> on uneven terrain. Typical examples of this category are the Seattle
> Lightfoot, Carbon Copy II and the Endolite foot.
>
> High performance feet (ie Flex-foot, Springlite) offer the highest energy
> return. These are the choice of runners, and those that value there
> performance on even terrain. These feet are relatively expensive and can
> be unforgiving on uneven ground. They cannot be combined with ankle
> units.
>
> Multi-axial feet are designed to accommodate variable terrains, allowing
> variable motion about the ankle. Depending on the design and the
> amputee's use, the may require more frequent maintenance. Like wise,
> these feet tend to be more expensive than the economy energy storage feet.
>
>
>
>
>
>
>
Citation
Levy, Charles, “FW:,” Digital Resource Foundation for Orthotics and Prosthetics, accessed November 6, 2024, https://library.drfop.org/items/show/214206.
